1. Field of the Invention
The present invention relates to an ophthalmic apparatus, and more particularly to a portable ophthalmic apparatus equipped with an illumination optical system for illuminating a specified point of a patient""s eye with slit-light, and an observation optical system for observing an image of the illuminated point of the eye via eyepieces.
2. Description of the Prior Art
Portable ophthalmic apparatuses include portable slit-lamps used for observing the anterior portion of a patient""s eye. Examples of such apparatuses are described in Japanese Utility Model Laid-Open Publication No. 24107/91 and Japanese Patent Laid-Open Publications Nos. 128036/91 and 164114/96. More recently, there are slit-lamps that can obtain electric images of the anterior portion of an eye.
With respect to ophthalmic apparatuses for observing the anterior part of an eye, it is desirable to be able to perform such observations using both eyes. Therefore, when the anterior portion is imaged electronically, the image optical path is split at the eyepiece part of the apparatus in prior arts. A problem with such an arrangement is that the observed image is degraded by a loss of light quantity and by the increase in the optical parts, and another problem is a difference between observed images and electronically captured images. One possible way around this is to capture the image from a different direction than the objective lens. However, the problem with this is that since the observed image and electronic image have different directions, it is difficult for the examiner conducting the examination to obtain the desired electronic images.
In the case of portable slit-lamps, there is also the problem of hand-movement that makes it difficult to obtain good images.
It is therefore an object of the invention to provide an ophthalmic apparatus that is able to reduce the difference between observed and captured images and can also obtain good observed images.
According to the present invention, an ophthalmic apparatus comprises an illumination optical system for illuminating a specified point of a subject eye with slit-light, an observation optical system including objective lenses for respectively forming an image of the specified point of the subject eye and left and right eyepiece systems for observing the image of the specified point with left and right eyes, an optical element disposed in a space that lies between the objective lenses and the specified point and between an effective diametric center of the left eyepiece system and an effective diametric center of the right eyepiece system, and an imaging device for capturing the image of the specified point which is guided thereto via the optical element.
An ophthalmic apparatus according to the invention includes a first unit and a second unit that can be detachably attached to the first unit. The objective lenses and left and right eyepiece systems are disposed in the first unit, and the optical element and the imaging device are disposed in the second unit.
With this arrangement, the optical member is located between the light path for left-eye observation and the light path for right-eye observation in order to guide the slit-image to the imaging device. This can substantially eliminate the differences between observed and captured images, and provide observation images with no degradation.
Further features of the invention, its nature and various advantages will be more apparent from the accompanying drawings and following detailed description of the invention.